Archastropecten crispatus
Archastropecten crispatus
Summary
Archastropecten crispatus was an astropectinid sea star, part of a lineage of mobile benthic predators adapted to unconsolidated sediment. Modern astropectinids move over and into sand or mud and commonly consume small molluscs and other invertebrates, making a similar predatory role a reasonable inference for this Eocene species.
Its skeleton consisted of many calcitic ossicles held together in life by soft tissues. After death these usually separated, so London Clay material is often represented by marginal plates or other isolated ossicles rather than a complete five-armed star.
Quick Identification
Look for: robust starfish marginal plates with a block-like outline and sculptured outer face; articulated arms are rare, so identification normally depends on matching several well-preserved marginal ossicles rather than any single fragment.
Diagnostic Features
- Marginal ossicles are robust and form the reinforced edge typical of astropectinid sea stars.
- Individual marginals have a consistent block-like outline and differentiated external and articular surfaces.
- Outer surfaces carry species-characteristic granulation or spine bases when unworn.
- Ossicle proportions differ from the broader goniasterid marginals of Teichaster stokesii.
- Species identification is strongest when a series of marginals from comparable arm positions is available.
Fossil Details
Similar Species
Recorded Fossil Sites
No fossil-site occurrences have yet been recorded for this species.
References
- Forbes, E. (1852). Monograph of the Echinodermata of the British Tertiaries. Palaeontographical Society Monograph View reference